The present invention relates to a release bearing assembly in a pull-type friction clutch, and more particularly, to a composite release sleeve for use in the release bearing assembly.
Generally, to shift a common pull-type clutch, a clutch pedal actuates a release fork within a vehicle clutch assembly. The clutch fork actuates a release sleeve which disengages a clutch disk assembly from an engine flywheel. The release sleeve is actuated axially along the rotating input shaft to transfer the linear clutch fork motion to the rotating clutch disk assembly. The release sleeve thus slidably supports the clutch fork and release bearing assembly directly on the input shaft. As the release sleeve is in constant contact with the rotating input shaft it must resist a great amount of frictional wear. The release sleeve is thus commonly fabricated from a high tensile steel material.
However, known steel release sleeves add to the weight of the release bearing assembly thereby increasing the actuation force necessary to operate the clutch fork and initiate a shift. Additionally, due to the similarity of materials, known steel release sleeves have been found to embedded material particles into the steel input shaft. After a number of operating cycles the embed particles increase frictional forces and wear between the shaft and the release sleeve. Such frictional increase may therefore lead to an undesirable increase in the pedal effort needed to release the clutch.